Process for making cupro-ammonium rayon spinning solution



' March 30, 1954 YOSHIO TSUNODA 2,673,811

PROCESS FOR MAKING CUPRO-AMMONIUM RAY-ON SPINNING SOLUTION Filed Sept. 29, 1950 OIL FEEDING- PIPE .9

CUPRO -AMMONI UM SOLUTION 8 "HEzT" OF" POLYSTYRENE OIL $DONGE IRON ALUMINIUM ALLOY 6 RUBBER I X Buzz/0 65 2/ Patented Mar. 30, 1954 PROCESS FOR MAKING CUPRO-AMMONIUM RAY-ON SPINNING SOLUTION Yoshio Tsunoda, Nobecka-Shi, Japan, assignor to Asahi Kasei Kogyo Kabushiki-Kaisha, Osaka- Shi, Japan Application September 29, 1950, Serial No. 187,554

Claims priority, application Japan August 31, 1950 2 Claims.

This invention relates to the remarkable improvement of the quality of cuprammonium rayon obtained from a spinning solution, the quality of which is improved by the radiation of supersonic Waves during the manufacturing process of the spinning solution. In the usual manufacturin process of cuprammonium rayon, cellulose such as cotton linter or pulp will be dissolved in an ammonia solution of copper hydroxide or in an ammonia solution of basic copper sulphate, to which alkali is added in order to make a spinning solution from which cuprammonium rayon will be made.

In this invention, I discovered that such cellulose as cotton linter or pulp will be made soluble in cuprammonium solution in a very short time by the radiation of supersonic waves during the manufacturing process of the spinning solution whereby the dispersion of cellulose compound becomes better, and therefore the viscosity of the spinning solution will be lowered in a short time without degrading the cellulose, and that the property of the product will be improved remarkably compared with the cuprammonium rayon spinning solution heretofore used. Such properties as tenacity, elongation, friction resistance, afiinity to dyestuffs, etc. in both the dry and wet state of the cuprammonium rayon thus spun from this spinning solution have also been improved.

Regarding the effect of the supersonic wave, theoretical researches were made in connection with its interfacial jamming effect, great acceleration, cavitation, stress inside liquid, etc, while various studies were made in its application to such as oil emulsification, electrolysis, fine grain photographic film emulsion, etc. Researches have also been made in the liquefaction of gell in connection with a colloidal solution of high molecular substances, and in lowering the viscosity of high molecular solutions. The supersonic wave has so far not been applied to the industrial manufacturing process of spinning solution of cuprammonium rayon, although it has been industrially applied to some extent to washing machines, emulsification of oils, etc.

The reason the inventor applied the radiation of the supersonic wave to the spinning solution of cuprammonium rayon during its manufacturing process is because it was discovered that the energy of the supersonic wave Works effectively on certain chemical reactions, especially interface between high molecular substances and solvents when a. high molecular substance undergoes swelling and is about to dissolve during the dissolving process, and it accomplishes the dissolution instantly and greatly improves the dispersion. It was also discovered during the manufacturing process of the new spinning solution that high molecular cellulosic raw materials, such as cotton linter or pulp, when dissolved in a cuprammonium solution of copper hydroxide or an ammonium and basic copper sulphate solution, to which supersonic radiation had been applied, dissolved m a very short time, the viscosity was greatly lowered and yet a spinning solution of a high degree of polymerization of cellulose and with good dispersion was obtained.

Also during the above-mentioned process, a supersonic Wave was radiated after the cellulose was dissolved, and a considerably improved degree of dispersion of the spinning solution, compared with the spinning solution of cuprammonium rayon heretofore used, was obtained.

To generate the supersonic wave, natural quartz or artificial crystal with similar properties were used and the phenomena of piezo-electricity applied, or nickel or other similarly magnetic metals used and the phenomena of magneto-striction r applied. The frequency of the former is several hundred kc./s. while that of the latter is generally 10-100 kc./s. the supersonic wave input to the Vibrator being generally about 5-20 watt/cm. of the sectional area. The difference in frequency, however, did not affect its application to this discovery. However, from the standpoint of industrial application, the latter is better than the former in point of mechanical strength, construction of vibrator, radiating sectional area, e c.

In order to radiate supersonic waves during the manufacturing process of this new spinning solution, a metal box of adequate size was attached to an outside wall of the dissolver and the supersonic wave vibrator installed inside this box. Then a sheet of alkali resistant substance (such as polystyrene) through which supersonic waves can easily pass, was inserted between this box and the dissolver, the inside of the box being filled with a transfer medium such as oil or water.

To dissolve cellulose by this new method, copper hydroxide or basic copper sulphate, aqua ammonia, water and a reducing agent such as sodium sulphite is added to the cotton linter or pulp, then stirred, and at the same time supersonic wave is radiated by the aforementioned method. Supersonic Wave can also be radiated, not during the dissolving process but after'the cellulose is dissolved by the ordinary process. When basic copper sulphate is used in the spinning solution, usually caustic soda is added. But with this new method, the amount of caustic soda can be cut down to the minimum or omitted altogether.

Ordinarily a spinning solution thus obtained is filtered through a nickel screen, deaerated in a vacuum tank whereby excess ammonia is reduced to 0.8-1.3 in its ratio to cellulose, and spun by the ordinary spinning process.

If the spinning solution is made by the new process, filtration and transportation become much easier due to the rapid drop of viscosity. The spinning operation also becomes easy because dispersion of the cellulose is made better and the yarn will be less nappy, while the degree of polymerization of the product will be very high because the degradation of the cellulose will be less. A cuprammonium rayon with excellent friction resistance and improved dyestuff sorption will result.

Fundamentally, the manufacturing method of spinning solution for use in the manufacture of staple fiber is the same as that for yarn, and as in the case of the above-mentioned cuprammonium rayon yarn, the inventor used a spinning solution of cuprammonium staple fiber made by the same method, manufactured cuprammonium staple fiber thereby and obtained an improved quality.

The electric input employed in the abovementioned process was -20 watt/cm. of the One kilogram of copper hydroxide (as of copper only) and 2.5 kilograms of purified cotton linter (as of linter free of water) were put into a .dissolver of 35-1-iter capacity into which 18 kilograms of aqua ammonia (as of 25% volume concentration) and 10.5 kilograms of water, were put. The contents were stirred and at the same time supersonic wave radiated while the purified cotton linter was being dissolved. The concentration of the dissolved cellulose in the spinning 1 solution was '7 .8 by weight.

A diagram :of the equipment used for this process is shown on an annexed drawing:

Explanation of drawing: 1 dissolver .of purified cotton linter which has an agitator 2. 5,

jacket through which water passes to cool the spinning solution from outside to keep it below 15 C. 3, vibrator for the oscillation of supersonic wave, made of iron-aluminum alloy. It is mounted on a rubber sponge I. A sheet of polystyrene ,is inserted between the box and the bottom part of the dissolver as shown in 4. Distance between vibrator 3 and sheet 4 is mm. Oil is used as the transfer medium 6 of supersonic wave. This oil circulates in the cooling circuit to .cool the heat generated by the vibrator. The vibrator 3 is connected with the vacuum tube oscillator by wire 3. The number of rotations of the agitator 2 is 10 R. P. M.

The .sectional area of the vibrator 3 is 9.5 cm.' 6 cm.=57 cm. The vibrator is agitated by the vacuum tube oscillator and vibrates at kc./s. The supersonic wave input to this vibrator is 1.2 kw. and 2.0 w./cm. The spinning solution thus manufactured showed the following Viscosity always shows a constant value as given in Nos. 1 and :2.

When supersonic wave was not radiated:

. 5 3O 60 1.5 2 3 4 Time min. min. min. hrs. hrs. hrs. hrs.

Viscosity:

NO. 1 1.880.. .190 170 170 150 148 148 NO. 2 S 85 r 74 67 '60 58 55 Dissolve 1 Undissolved.

2 Completely dissolved.

As shown in Nos. ,1 and 2, the experiments have poor reproducibility. Viscosity was tested against time .used by a steel ball falling a distance of 5 cm. in the spinning solution.

As shown above, when supersonic wave was radiated, the time of dissolution was very short, viscosity extremely low and :yet a spinning solution with a good cellulose dispersion was obtained.

Example 2 Same equipment as used in Example 1 was used, whereby basic copper sulphate,

which is generally used in factories, was employed. Basic copper sulphate, 1.2 kgr. (as of copper), purified cotton linter, 2.5'kgr., aqua ammonia (NH3 25% volume concentration), 18 kgn, caustic soda, 2,000 cc. (12% volume concentration), and water, 10 kgr. were used under the same conditions as mentioned in Example 1. The result is shown in the following chart.

When supersonic wave was radiated:

5 30 60 1.5 2 3 1 4 Time min.. min. min. hrs. hrs. hrs. hrs.

Viscosity:

No.1 "sec" 5 5 5 :5 5 5. -5 No. 2-- sec..' 5 5 '5 5 5 5 '5 Dissolved L I (9 1 Completely. I I 7 As given in Nos. 1 and 2, the viscosity always shows a constant value.

When supersonic wave was not radiated.

2 3 4 Time min. min. hrs. hrs. hrs. hrs.

Viscosity: i

No. 1 sec.. 89 80 75' 74 73 N0. 2.- 0-. 88 7O 59 49 48 46 Dlssolved (1) (1) 1 1 2 (2) v z 1 Undissolved.

2 Completely dissolved.

As shown in Nos. 1 and 2, the experiments have poor reproducibility. Above viscosity was tested against the time used by a steel ball falling a distance of -5 cm. in the spinning solution.

As in Example 1, the time of dissolution is very short, viscosity extremely low and a sp in solution with a good dispersion obtained.

When supersonic wave is not radiated, it is absolutely necessary to use the above amount of caustic soda in order to dissolve the cellulose. If the amount of caustic soda is reduced, or if none is used, th cellulose remains undissolved and it is impossible to obtain a spinning solution. As mentioned before, the radiation of supersonic wave reduces the amount of caustic soda used, or makes its use altogether unnecessary.

A spinning solution manufactured by the supersonic wave radiation method, as explained in Examples 1 and 2 requires a very short time for dissolution, and therefore, the cellulose undergoes less degradation, while the de ree of polymerization can be kept high, as shown below. In the following, purified cotton linter with an average degree of polymerization 1150 was used as the cellulosic raw material, and no oxidization preventive was employed nor was air replaced by nitrogen.

Time of Supersonic wave radiation hrs hm hrs Degree of polymerization of regenerated cellulose from the spinning solution to which supersonic wave was radiated Degree of polymerization of regenerated cellulose from the spinning solution to which supersonic wave was not radiated A spinning solution manufactured by the above process, radiated with supersonic wave, is filtered, deaerated, excessive ammonia, if any, removed, and a spinning solution with a 1:1 ammoniaoellulose ratio can be obtained. The solution can be used with the Hank type spinnin machines, then treated from 40 to 60 minutes in water, and made into the finished product after the usual securing and drying process. The result is as Suprammonium rayon thus manufactured shows good friction resistance, adsorbs and absorbs a just adequate amount of dyestuff under equilibrium condition, and takes a long time before it reaches the equilibrium condition. It is explained in the following experiment:

Two grams of the sample is put into a vessel, the diameter of which is 9.6 cm. and capacity 700 cc. Then 30 porcelain balls of 2.5 cm. in

diameter are put into the vessel. The vessel is revolved 50 R. P. M. for 30 minutes at a temperature of 20 C. with 65% relative humidity and then brought to a stop in order to prevent the temperature from rising. It is then put into rotation after 5-6 hours cooling. This routine is repeated until the total actual time of rotation is 6 hours. The percentage of the yarn that is pulverized by this test to the total amount of the sample is as follows:

Destroyed percentage Rayon yarn radiated with supersonic wave 0.60 Rayon yarn not radiated with supersonic wave 2.60

The result of the dyeing test of 2 grams of the sample with 100 cc. solution of 0.5% Japanol Brilliant Blue 6BKX and 2.5% NaCl under a temperature C. is shown below:

It has also been taken into consideration that the various improvements in detail will not deviate from the scope and spirit of the discovery. However, the new process will not be limited provided that it is defined by the following claims.

I claim:

1. A process for making a cupro-ammonium rayon spinning solution which comprises the step of dissolving cellulosic raw material in a cupro ammonium solvent, and radiating supersonic waves from a supersonic vibrator through said solution, the supersonic wave input to the vibrator being about 5 to about 20 watts per square centimeter of the cross-sectional area.

2. A process for making a cupro-ammonium rayon spinning solution which comprises the step of dissolving cellulosic raw material in basic cupro-ammonium solvent and caustic soda solution, and radiating supersonic waves from a supersonic vibrator through said solution, the supersonic wave input to the vibrator being about 5 to about 20 watts per square centimeter of the cross-sectional area.

YOSHIO TSUNODA.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 978,878 Guadagni Dec. 20, 1910 1,869,040 Bassett July 26, 1932 1,992,938 Chamber Mar. 5, 1935 2,163,649 Weaver June 27, 1939 2,360,893 Robinson Oct. 24,1944 2,484,013 Calhoun Oct. 11, 1949 FOREIGN PATENTS Number Country Date 477,646 Great Britain Jan. 4, 1938 OTHER REFERENCES Wood: Phil Mag & Journal of Science, Sept. 4:, 1927, pp. 417, 428 and 430. 

1. A PROCESS FOR MAKING A CUPRO-AMMONIUM RAYON SPINNING SOLUTION WHICH COMPRISES THE STEP OF DISSOLVING CELLULOSIC RAW MATERIAL IN A CUPROAMMONIUM SOLVENT, AND RADIATING SUPERSONIC WAVES FROM A SUPERSONIC VIBRATOR THROUGH SAID 